The proposed research seeks to evaluate CNS side effects of antihypertensive therapies by means of a multidimensional, psychobiological assessment methodology. Of particular interest are the effects of treatment on sleep architecture, cognitive and perceptual-motor performance, mood state, and sexual function. Additionally, the potential role of peripheral (circulatory and metabolic) processes as determinants of fatigue and other CNS effects will be investigated. In order to assess the effects of treatment in chronically medicated and untreated patients, three complimentary studies are proposed: Study I will consist of a matched comparison in which 48 male hypertensive patients receiving long-term propranolol therapy will be compared to a matched group of patients on clonidine. Two cohort groups will be selected for evaluation within each drug condition, and an equal number of symptomatic and asymptomatic patients will be included. The purpose of the study is to identify patterns of CNS effects associated with patient complaints of drowsiness and fatigue, and to test hypotheses concerning the mediation of these effects. Study II is a prospective, experimental evaluation of 80 untreated male hypertensive patients, in which 48 patients will be randomly assigned to pharmacological (propranolol, clonidine, placebo), and 32 patients to non-pharmacological treatment. Complete psychobiological assessments will be conducted before and after each treatment phase. Study III consists of a partial replication of Study II, in which elderly males with isolated systolic hypertension will receive propranolol, placebo, or non-pharmacological therapy. The latter studies will investigate biobehavioral sequellae of adrenergic-inhibiting and non-pharmacological therapies in untreated male patients. Taken together, these studies will provide an in-depth evaluation of CNS side effects associated with antihypertensive treatment, and will be of value in the clinical management of hypertension.